We present a multifunctional endoscope capable of imaging, fluid delivery and fluid sampling in the alveolar space. The endoscope consists of an imaging fibre bundle fabricated from cost effective OM1 PCVD graded index preforms made for the telecommunications market. These low-cost fibres could potentially make our endoscope disposable after a single use. The performance of our low-cost imaging fibre bundle is shown to be comparable to the current commercial state-of-the-art. The imaging fibre bundle is packaged alongside two channels for the delivery and extraction of fluids. The fluid delivery channels can be used to deliver fluorescent smart probes for the detection of pathogens and to perform a targeted alveolar lavage without the removal of the imaging fibre as is currently standard procedure. Our endoscope is fully biocompatible and with an overall outer diameter of 1.4 mm allowing it to fit into the standard working channel of a bronchoscope. We demonstrate the use of our endoscope in ex-vivo human lungs. We show alveolar tissue and bacterial imaging over two wavelength bands 520 nm – 600 nm and 650 nm – 750 nm both commonly used for bacterial smart probe detection.
We present a toolkit for a multiplexed pH and oxygen sensing probe in the distal lung using multicore fibres. Measuring physiological relevant parameters like pH and oxygen is of significant importance in understanding changes associated with disease pathology. We present here, a single multicore fibre based pH and oxygen sensing probe which can be used with a standard bronchoscope to perform in vivo measurements in the distal lung.
The multiplexed probe consists of fluorescent pH sensors (fluorescein based) and oxygen sensors (Palladium porphyrin complex based) covalently bonded to silica microspheres (10 µm) loaded on the distal facet of a 19 core (10 µm core diameter) multicore fibre (total diameter of ~150 µm excluding coating). Pits are formed by selectively etching the cores using hydrofluoric acid, multiplexing is achieved through the self-location of individual probes on differing cores. This architecture can be expanded to include probes for further parameters. Robust measurements are demonstrated of self-referencing fluorophores, not limited by photobleaching, with short (100ms) measurement times at low (~10µW) illumination powers.
We have performed on bench calibration and tests of in vitro tissue models and in an ovine whole lung model to validate our sensors. The pH sensor is demonstrated in the physiologically relevant range of pH 5 to pH 8.5 and with an accuracy of ± 0.05 pH units. The oxygen sensor is demonstrated in gas mixtures downwards from 20% oxygen and in liquid saturated with 20% oxygen mixtures (~8mg/L) down to full depletion (0mg/L) with ~0.5mg/L accuracy.